大型零件精冲尺寸精度控制

针对钢板的各向异性以及制件外形的非对称性所导致的精冲零件非规则变形的问题,以某汽车变速箱连接板零件为例,根据其结构特点、尺寸精度和所需精冲力大小,拟定了先落料后冲孔的精冲方案。通过试验研究了在不同材料轧制方向下,制件渐开线齿形内孔的跨齿距、齿顶圆、齿根圆以及4个圆孔位置度尺寸的变化规律。根据试验获得的制件尺寸与模具设计尺寸之间的差异,采用尺寸补偿方法,对精冲模具尺寸进行优化设计,进而加工出符合图纸精度要求的制件。为便于模具维护,对冲孔精冲模具的齿形孔凸模采用了特殊的上、下分体式设计。实际生产应用表明,制件渐开线齿形内孔尺寸及4个圆孔的位置度尺寸稳定,精度能够达到图纸要求。

Size accuracy control of large-scale parts on fine blanking

Aiming at the problem of irregular deformation for fine blanking parts caused by the anisotropy of steel plate and the asymmetry of part shape,taking an automobile gearbox connection plate as an example,according to its structural characteristics,size accuracy and required fine blanking force,the fine blanking process of first blanking and then punching hole was drawn up.The changing lows of distance between two teeth,the top circle,the root circle in the tooth-shaped inner hole of involute profile and the position degree of four urcular holes were studied by the tests under different rolling directions of materials.According to the difference between the size of parts and the design size of die obtained from the test,the size compensation method was used to optimize the size of fine blanking die,and the fine blanking parts that met the requirements of the drawings were obtained.In order to facilitate the maintenance of die,a special upper and lower split design was adopted for the punch of tooth-shaped hole in the fine blanking die.The practical application shows that the inner hole size of involute profile and the position degree of four circular holes are stable,and the size accuracy meets the requirements of the drawings.